(1) Field of the Invention
The present invention relates to a system and method for recognizing that a vehicle is operating in a traffic stagnation state.
(2) Description of the Background Art
When the vehicle runs in a traffic stagnation state, it is preferable for an acceleration to be reduced with respect to a depression of (angular displacement of) an accelerator pedal than a normal running state since a driving operation to avoid a collision against a preceding vehicle and to follow behind the preceding vehicle becomes easy and the fatigue of the vehicle driver is, therefore, relieved. Consequently, a safer driving is achieved.
Japanese patent Application First Publication No. Showa 59-200848 published on Nov. 14, 1984 exemplifies a control system for an automatic transmission in which when the vehicle runs in traffic stagnation, the system recognizes it and deviates a shift lever position diagram of the automatic transmission toward a lower gear position at an early stage. In the above-described control system, when an average value of the vehicle speed measured at a regular time interval within a predetermined time and a median value of an accumulated distribution of the acceleration in the vehicle forward direction measured together with the vehicle speed, are below a respective predetermined value, the system determines that the vehicle runs in the traffic stagnation.
However, the recognition of the traffic stagnation is carried out only after some amount of data on the vehicle speed and acceleration have been collected and, hence, the recognition of the traffic stagnation cannot be carried out until some time after the vehicle has started to run.